Sourcing caps for a revamped express build and other suggestions.

[Fuzzaliciousness]

I believe I posted this in the wrong section first and can’t figure out how to delete

Hello all! I built an express clone about 15 years ago thanks to the wealth of info on this site. It was my second amp build and I got lucky with only missing one ground and it firing up on the second try. Unfortunately I had to sell it shortly after due to divorce and child support. It’s cheaper to keep her applies to multiple variables in this story. Not my choices though.

Fast forward to today. I purchased a clone off reverb with a beautiful cab. Opening it up, I find that it is a Ceriatone expression. Nothing wrong with that. It sounds pretty darn good, but honestly I think my build did the clean to mean, touch sensitivity, and the harmonic sustain feedback thing better. It has a choke and some other mods. From doing some reading it sounds like the choke might be part of the problem.

Long story short I was planning on upgrading some components and getting it a little closer to what I remember. I have been out of the express world for quite some time. It seems rather hard to source original Mallory filter caps. What are my options for sourcing those or comparable caps.

How much difference would you think MM transformers would make?

Any other advice is welcome. Thank you all.

[Roe]

I recommend bc vishay axials 450v. for the first filter cap, even the JJ 80uf 500v works.

Forget MM, get pacific, at least for the OT

[Colossal]

Fuzz,

I recommend you contact RJ of RJ Guitars. He still has a supply of the original Mallory PVC polyester film foil coupling capacitors, Pacific Output transformers (wound with a dual tap at 5k2 and 6k6), the original Belden wire Ken Fischer used, and I think maybe still a few of the Mallory filter caps depending on how far down the rabbit hole you want to go.

[bcmatt]

I think a key element might be the output transformer specifically.
Traditionally the Express has 6.6k primaries for the OT. I've heard that ceriatone was using a much lower primary impedance on their Trainwreck clones... Like maybe about 4.3k or something. This would make it bolder and brighter, louder and less compressed (Or so I've heard).

Theoretically, you could disconnect the OT and test what ratio it actually has. You could also email Nik at ceriatone and ask him what primary impedance it has. Is there a year of production written inside somewhere? I'm curious if he ever adjusted his OT designs at some point to align more with the original Trainwrecks as more info came out.

[Roe]

I think a key element might be the output transformer specifically.
Traditionally the Express has 6.6k primaries for the OT. I've heard that ceriatone was using a much lower primary impedance on their Trainwreck clones... Like maybe about 4.3k or something. This would make it bolder and brighter, louder and less compressed (Or so I've heard).

Theoretically, you could disconnect the OT and test what ratio it actually has. You could also email Nik at ceriatone and ask him what primary impedance it has. Is there a year of production written inside somewhere? I'm curious if he ever adjusted his OT designs at some point to align more with the original Trainwrecks as more info came out.

the early Ceriatone ones had dual primaries: 5k2 and 6k6. In the famous comparison by Geetarpicker, the 5k2 was used, making the Ceriatone louder than the original. These days, you rarely see the 5k2 specs anymore

[bcmatt]

I think a key element might be the output transformer specifically.
Traditionally the Express has 6.6k primaries for the OT. I've heard that ceriatone was using a much lower primary impedance on their Trainwreck clones... Like maybe about 4.3k or something. This would make it bolder and brighter, louder and less compressed (Or so I've heard).

Theoretically, you could disconnect the OT and test what ratio it actually has. You could also email Nik at ceriatone and ask him what primary impedance it has. Is there a year of production written inside somewhere? I'm curious if he ever adjusted his OT designs at some point to align more with the original Trainwrecks as more info came out.

the early Ceriatone ones had dual primaries: 5k2 and 6k6. In the famous comparison by Geetarpicker, the 5k2 was used, making the Ceriatone louder than the original. These days, you rarely see the 5k2 specs anymore

Oh cool! That's impressive that Ceriatone have the option. My Liverpool OT that I got from Moose at Toneslut also has 5k2 and 6k6. There were rumors for each value over the years it seems, and I definately noticed the difference as I've continued to go back and forth.

[Fuzzaliciousness]

This one has the Ceriatone 6.6K and 5.2K and you can select between the two on a switch. It also has the power transformer voltage selectable between 300v and 260v. Shortly after posting this originally, I found a MM KF 0T nos on eBay for a pretty good price. I scooped it up but have not installed it. It also has 6.6k and 5.2k. I think I’m going to add a switch, put the 1k25 watt resistor back in and make those selectable.

[bcmatt]

This one has the Ceriatone 6.6K and 5.2K and you can select between the two on a switch. It also has the power transformer voltage selectable between 300v and 260v. Shortly after posting this originally, I found a MM KF 0T nos on eBay for a pretty good price. I scooped it up but have not installed it. It also has 6.6k and 5.2k. I think I’m going to add a switch, put the 1k25 watt resistor back in and make those selectable.

So you are going to be able to switch back and forth between the choke and the 1K resister? Let us know how you find the difference. I'm curious. I used a resister on my Hot Cat conversion build instead of a choke to save money... Figured it worked well on my Liverpool and Express, so it should be fine for a Hot Cat too.

[Roe]

After I got pacific OTs, I moved my ceriatone OT to another amp. I'm using the 5k2 but got it switchable

[Fuzzaliciousness]

Yes I’m going to make the resistor and choke selectable.

[Roe]

Yes I’m going to make the resistor and choke selectable.

with a choke instead of the 1k resistor, the screens will overdissipate. and the bias changes

[Fuzzaliciousness]

Yes I’m going to make the resistor and choke selectable.

with a choke instead of the 1k resistor, the screens will overdissipate. and the bias changes

Thank you. All info is welcomed because I’m no expert on amps. I have only built a few more than a handful.
The choke was already installed in this one and I’m wanting to add the resistor to get it closer to original specs. Putting it in on a switch seemed a good option even though it will probably be on the resistor setting usually.

[Fuzzaliciousness]

I can’t believe it has been almost a year since I first posted this. I have had many other projects and priorities. I did, however, start and complete this today. Initial thoughts, I like the Mercury Magnetics transformer better and the resistor setting better. It seems to have much more of the harmonic feedback bloom. To me it sounds much more wreckish ( I’ve never played a real one but YouTube and other research has given me a good idea). Before, it sounded more like a Marshall on steroids with some wreck vibes.

[Colossal]

Good work. Thanks for the report. I've also used the Mercury KF-TW-OT in the past with very good results.